Three-way distributing valve



Patented Mar. 25,1941

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` l'rnaEE-wnr ms'rnraUTlNG vALvE Selden 'l'. Williams, Bellerose, N. Y.,assignor to Scovill Manufacturing Company, Waterbury, Conn., acorporation of Connecticut original application November so, 193s.serial No. 243,220. Divided and this application January 3, `1940,Serial No. 312,231

4 Claims. (Cl. 277-21) This application is'a division oi my priorapplication, Serial No. 243,220, led November 30, 1938.

My present invention relates toa distributing valve intended for use insafety control devices for power presses and the like, and moreparticularly to such safety devices which are pneumatically controlled.

The prevention of injury to press operators of power presses has longreceived the attention of safety engineers and laborboards and much hasbeen done to reduce the hazards of personal injury incident 4to pressoperations. `Various forms of safety appliances in the nature of safety`1:5 clutches. electrical devices, and mechanical shields, have beendevised, and while these have met with varying degrees of successl andrecognition, on the whole they have been open to one objection oranother. Among the primaryobjections o met with by these safety `devicesare: (1)y their tendency to slow down the press operations; (2) theirhigh installation cost; (3) "their noir-foolproof character; and (4)their safety characteristics could be circumvented by anoperator whodesired to speed up production. Y

My present invention provides a three-way y distributing valve as anessential element of a safety device for power presses and the likewhich overcomes the various objections and limitations above mentioned.In its underlying concept my invention embodies in combination with anovel form of cutout valve which relies upon compressed air to operate aplunger for tripping a clutch on the drive shaft of the press or foroperating an equivalent means, a plurality of control or distributingvalves so disposed with relation to the operating head of the press thatboth hands of an operator `must be used to operate said valves and bewell away from danger when doing so; and further, said valves areshielded so that they can not be accidentally operated. My invention iscapableoi installation on machines that are equipped with eithernon-repeat or repeating type clutches.

45 The principle, construction `and operation of my invention will bebetter understood from the detailed description which follows whenconsidered in connection with the accompanying drawing which shows apractical embodiment of my 50 invention, and wherein:

Figure 1 is a perspective view of a power press showing my inventionapplied thereto.

Fig. 2 is a longitudinal section through one of the manually operablevalves forming the essence 55 of my invention herein claimed.

Fig. 3 is an axial section through an automatic pressure operatedcut-out valvel adapted for use with the present invention.

Although my invention is capable of use with any type of press ormachine which has a movable head adapted to move toward and away from acomplemental member and between which members the hands of an operatormust be `positioned in the handling of the work to be operated upon bythe machine, I have shown my safety device 10 applied to `a power pressA of conventional design having a movable head I0 which carries a die Ilfor cooperation with a complemental die I2 mounted on the base of thepress. The head I0 is reciprocable so as to bring` the dies II and I2 15into operative position to the work being acted i upon, thereclprocation of the head I0 is provided by rotation of the shaft I3upon which is mounted a clutch (not shown) of any approved type. Asherein shown, the clutch'is adapted to 20 be tripped by a clutch trip I4carried by a rod l5, one end of which carries a piston I6 mounted in acylinder I'l which is shown as pivotally mounted at I8 to the pressframe.

For operating the clutch trip only when the 25 hands of the operator arewell away from danger,

I have provided a pair of manually operable valves B and B2 and acut-out valve C which form part of a pneumatic circuit adapted toestablish fluid communication between the interior 30 of the cylinder Ilwith a source of compressed air, The structures and functions for thevalves B, B2. and C, will be presently described.

The manually operable three-way distributing valves B and B2 areidentical in construction and 35 each consists of a hollow casing I9having lateral tubular oiisets or projections 2li and 2I providinginduct and educt openings, respectively, in the casing. Within thecasing between the lateral offsets is a shoulder upon which is `mounteda valve packing seat 22 which is held in place by a tubular plug 23having lateral openings 24 therein, the said plug beingscrew-threadedlyor otherwise held in position within the casing. Mountedwithin the casing for engagement with the packing seat 22 is a valvecheck member 25, the lower portion of which is hollowed out and enclosesa helical spring 26 for normally holding the valve against its seat. Thevalve check 25 above the seating portion thereof is formed with an axialDin 2l, the upper end 28 of which is of tubular form and of a diameterto snugly slide through the axial opening in the tubular plug 23, andsaid tubular portion of the pin, at its lower end, is formed withlateral openings 29. To insure against leakage and to provide an airseal between the top o1' the tubular plug 23 and the top of the hollowportion 28 of the valve pin 21, I connect said parts together by atruncated conef shaped, tubular packing 30. Any suitable means may beemployed for holding this packing in contact with said parts. and asherein shown, the packing which is formed as a separate part has asliding flt with the hollow portion of the valve check pin and is heldin clamping engagement with the tubular plug 23 by a tubular member 3|which screw-threadedly engages within the casing I9. Mounted fortelescopic movement within the tubular member 3| is a plunger 32, theinner end of which is recessed or formed with a socket 33 to engage overthe open end of the hollow portion of the valve check pin and the freeend of the tubular packing 30 to seal said open end of the valve pinwhen the plunger is depressed in the act of unseating the valve check25. The plunger 32 is of a length to extend beyond the top oi' thetubular member 3| and is normally urged outwardly by a helical spring 35mounted between a shoulder within the tubular member 3| and a shoulderon the plunger 32. For limiting the extent of the plunger movement andfor holding it against separation from the tubular member 3|, theplunger is formed with a slot 36 through which extends a pin 31 carriedby the tubular member. For facilitating movement of the plunger by thehand of an operator, the plunger at its outer end is provided with anenlarged mushroom head 34. The tubular lateral offsets 20 and 2| areeach threaded for connection with screw-threaded nipples 38, to whichare attached sections of hose or iiexible conduits 39, 391, 392, and393, forming a part of the pneumatic circuit. The tubular member 3| isalso formed with a lateral opening or vent 40 which, it will beobserved, provides open communication through the tubular portion 28 ofthe valve check pin and the lateral openings 24 in the tubular plug 23,with the bore through the lateral oiiset 2|, the educt opening of thevalve B, when the check valve 25 is seated. When the valve check 25 isunseated it will be appreciated that this open communication is cut offby the seal provided by the engagement of the lower end of the plunger32 with the coned packing 30.

The automatic pressure operated cut-out valve C consists of a casingformed of a central substantially cylindrical tubular element 4|, theends of which are screw-threadedly connected to tubular end members 42and 43, each of which terminates in an outwardly-directed nipple 44 towhich an end of the conduits 391 and 392 are suitably connected. Mountedwithin the casing provided by the elements 4|, 42, and 43, is a tubularmember 45 having a bore substantially flush with the bore through thenipple end of the element 42 and having an outwardly directed flange 46which is clamped against a nat surface in the element 42 by thescrew-threaded connection between said elements 4| and 42. Surroundingthe tubular element 43 in slightly spaced relation thereto is a tubularplunger check valve 41 which at its end adjacent the flange 48 is formedwith a iiange 48 and carries a piston packing 49 having a diameter toair-tightly move within the -cylindrical bore of the element 4|.

Surrounding the plunger check valve 41 and bearing at one end againstthe flange 48 is a helical spring 50, the opposite end of which bearsagainst an inwardly-directed ilange 5| on the tubular element 4| for thepurpose of exerting a force upon the plunger valve for normally holdingit in its unseated position as shown in Fig. 3. The plunger valve 41 atits other end is closed and formed with an annular ring 52 rearwardly ofwhich the plunger valve is formed with lateral openings 53 leading fromthe interior of the tubular plunger to the duct through the cut-outvalve. The closed end of the plunger valve is adapted to engage a valveseat packing 54 mounted within the tubular element 43 and held therein.by a sleeve 55 which is clamped between the annular ilange 5| and saidpacking in the assembly of the elements 4| and 43, there being alsoprovided a packing 58 between the sleeve 55 and the flange 5|, whichpacking engages the outer wall of the plunger valve 41 to provide anair-tight seal therewith. The packing 54 consists of two washers whichare pressed over a tubular sleeve 51 having an outwardly-directed ilangeor rib 58 intermediate its ends. 'I'he element 43 between the nipple 44thereon and the packing 54 therein is formed with a chamber having aspider 59 for guiding the stem of a iloating valve 60, the face thereofwhich engages the packing 54 being o1' conical form and of smallereifective area than the opposite face of said valve. The function forthis construction will presently be explained. To prevent tampering withthe cut-out valve parts, they are housed within a shell 60a having avent opening h. The tubular element 4| also has a vent opening 4|a forpermitting the venting of any air under pressure which may nd its wayinto said element.

'I'he manually operable distributing valves B and B2 may be convenientlyattached to the machine by means of brackets 18 which are bolted to theends of the bed of the press. These brackets may also conveniently carryshields 19 which extend above and partially encircle the mushroom heads34 of the valves B.

The device hereinbefore described is intended for tripping a clutch ofthe non-repeat type.

Operation- The right hand operating valve B2 must be pressed downslightly in advance or the left hand operating valve B or simultaneouslytherewith. When this is done the compressed air from the source passesthrough the pneumatic circuit into the cylinder |1 and forces the pistondownwardly, which action trips the clutch and operates the press. Whenthe operating valves B and B2 are opened in the manner specified, a puffor surge of air passes through the pneumatic circuit to act upon thepiston, and after so acting, the incoming air pressure operates to movethe plunger valve 41 of the cut-out valve C against the seat 54, andsaid valve will rem-ain seated so long as the left hand operating valveB is held open. When the hand is removed from the left hand operatingvalve B, the check valve 25 therein will seat under the force of thespring 26, the compressed air entrapped in the cut-out valve C will ventthrough the opening 40 in the valve B and permit the plunger valve 4,1to unseat. When the hand is removed from the right hand operating valveB2, the air from the cylinder |1 will vent through the opening 40 insaid valve. As the air is released from the cylinder |1 the clutch tripI4 is returned to its operating position and the press cannot againoperate until the clutch is again tripped.

If either ofthe manually operable valves B or B2 is tied down or helddown, the cut-out valve C functions to prevent the piston in thecylinder from operating the clutch, because, as above described, if theleft hand valve Bis held down. the

plunger valve 41 will remain seated and prevent the passage of airthrough the pneumatic circuit to the cylinder. while if the right handoperating valve B2 is held down, the press will operate once; and onceonly, as the check valve 60 of cut-out valve C holds the air in thepiston and will not let it return. Furthermore, as the effective area ofthe valve 60 acted upon by the trapped back pressure in cylinder I1 isgreater than the effective area of the seating face of said valve, itwill be apparent that the incoming air through the cut-out valve C uponunseating of valve B will be insufficient to unseat the valve 60.

It will thus be seen that the safety device is effective to preventpress operation if any attempt is made by the press operator to have oneof his hands free during the tripping of the press.

The safety device, it will be understood, is subject -to modification inconstructlonal features and to various uses within the range ofengineering skill, without departing from the spirit of the invention.

What I claim is:

1. A distributing valve comprising a casing having therein a valve seat,a check valve normally held against said seat, an induct opening and aneduct opening on opposite sides of the valve seat, a vent opening on thesame side of the valve seat as the educt opening, a tubular plug forholding the valve seat in place, the valve check having a stem with apassage therein slidably extending through the tubular plug. saidtubular plug having lateral openings therein establishing opencommunication between the educt opening and the passage in the valvecheck stem, and air sealing means between the tubular plug and themovable valve check stem.

2. A distributing valve according to claim 1, wherein the air sealingmeans between the tubular plug and the valve check stem is flxedlycarried by the hollow plug and slidably engages the movable valve checkstem.

3. A distributing valve comprising a casing having therein a valve seat,a check valve normally held against said seat, an induct opening and aneduct opening on opposite sides of the valve seat, a vent opening on thesame side of the valve seat as the educt opening, a tubular plug forholding the valve seat in place, thevalve check having a stem with apassage therein extending through the tubular plug, said tubular plughaving lateral openings therein establishing open communication betweenthe educt opening and the passage in the valve check stem, a truncatedconical tubular packing between the tubular plug and the movable valvecheck stem, the larger end of said packing being xedly carried by thehollow plug and the other end of said packing slidably engaging themovable valve check stem and a, secondary, normally unseated valvemanually operable from the exterior of the casing having a socketadapted to engage over the open end of the movable valve check stem andthe free end of the conical tubular packing adapted to closecommunication between the vent opening and the educt opening by closingthe passage through the check valve stem and substantiallysimultaneously therewith unseat the first mentioned check valve.

4. A distributing valve comprising a casing having therein a valve seat,a check valve normally held against said seat, an induct opening and aneduct opening on opposite sides of the valve seat, a vent opening on thesame side of the valve seat as the educt opening, a tubular plug forholding the valve seat in place, the valve check having a stem with apassage therein extending through the tubular plug, said tubular plughaving lateral openings therein establishing open communication betweenthe educt opening and the passage in the valve check stem, air sealingmeans between the tubular plug and the movable valve check stem, and asecondary normally unseated valve manually operable from the exterior ofthe casing adapted to unseat the check valve and simultaneously engagethe air sealing means be tween the movable stem of the check valve andthe hollow plug to seal the passage in said stem and to closecommunication between the vent opening and the educt opening.

SELDEN T. WILLIAMS.

